Technical Field
This disclosure relates to memory devices, and more particularly, to post-packaging repair of a memory device.
Description of Related Technology
Memory cells of memory devices such as dynamic random access memories (DRAMs), static RAMs (SRAMs), flash memories, or the like can experience defects leading to errors and/or failures. In some cases, memory cells can be identified as defective (hereinafter “defective memory cells”) after the memory device (e.g., a memory chip) has been packaged, such as in cases where the memory cells were not defective before the packaging process. Examples of packaging include, but are not limited to, encapsulation by epoxy, ceramic packages, metal/glass packages, and the like. After a memory device has been packaged, the memory device can be tested to identify defective memory cells. Addresses mapped (e.g., assigned) to defective memory cells can be remapped (e.g., reassigned) to functional memory cells (e.g., memory cells that have not been identified as defective) so that the memory device can still be effective.
Non-volatile memory (e.g., programmable elements, such as fuses or antifuses) can be programmed to store data corresponding to one or more addresses mapped to defective memory cells. One example of a group of programmable elements is a row of antifuses. An antifuse has a high resistance in its initial state. An antifuse can permanently create an electrically conductive path when a relatively high voltage is applied across the antifuse. An antifuse can have a structure similar to that of a capacitor, i.e., two conductive electrical terminals are separated by a dielectric layer. To create an electrically conductive path, a relatively high voltage is applied across the terminals, breaking down the interposed dielectric layer and forming a conductive link between the antifuse terminals. Creating a conductive path through an antifuse is referred to as “blowing an antifuse.”
Certain protocols exist for performing post package repair. Post package repair can involve blowing antifuses. Blowing an antifuse can be performed in an antifuse programming time, which can be on the order of 200 milliseconds (ms). In some applications, such a delay can undesirably impact performance of a memory.
Accordingly, a need exists to improve post package repair.